Apparatus for pumping drilling fluids



"-27 PCenfrifugal Pump I I 26 11 f A INVENTOR. I Douglas Ragland, BY

July 7, 1953 D. RAGLAND v 2,644,401

APPARATUS FOR PUMPING DRILLING FLUIDS Filed March 15, 1951 4 Sheets-Sheet 1 (uh. v

I I Mill/1mm July 7, 1953 0. RAGLAND 2,644,401

APPARATUS FOR PUMPING DRILLING FLUIDS Filed March 15, 1951 4 Sheets-Sheet 2 IN VEN TOR.

2 Doug las Rag/and,

BY 7a.

AGENT.

July 7, 1953 D. RAGLAND 2,6 0

APPARATUS FOR PUMPING DRILLING FLUIDS Filed March 15, 1951 4 Sheets-Shgeif. 3

Non-compressible Fluid Mud Non-canpressibl Fluid enfrifug 0/ Pump IN V EN TOR.

July 7, 1953 I D. RAGLAND 2,644,401

APPARATUS FOR PUMPING DRILLING FLUIDS Filed March 15, 1951 -4 Sheets-Sheet 4 IN VENTOR. Doug/,as Ragland,

seis de UNI-TED SIA'ELS PAT Q F QE Amg n g qs 'FQR PUMPING DRILLING "FLUIDS""' Douglas; England, Houston, Tex, assignor, by mesneka ssignmems, to Standard.- Oil llvelop merit;

w; ei w 14 rnoeiimi ApglieationMareh 15, 195.1, Serial-No. 2715,782

The present invention isdirected: to appagaflius er-'1 pu p ng-flu ds More. pert cula lx t e nvention is directed to improved; eppe rat us' for pumping drilling fluid comprising a. suspeneion of ne ynivideds idse nn flu dmed um-r rhq eppe at e fg he. resent nven i n may b described briefly-es involving e plu 'ality oi interc n e d. e l e nin ch mbe a a te to -z n ein o v -o m ur wh ch e ves as, a liq iston,- end. which eq ri q ie b ween the m ersach-pfihe nihe s sipm ieewi an nle amen. utle W iQh' ha fnsifi refiisi th 19 of uid n i eci enl o p fit no w hr u hs d nl t. nd; uile A Qus he'd ning p ssa e a s commun c es; ith ea h of se s 'c emh hr u liqq m l-it .qo ilienet qand a pump is conneeted i; Q.,ti1ep-e-ssageways in ai hous n by Q dn i-s: d fie 5 1 i le end-"@111 Qui ei t e e o, nac uatin imhev ee in ey flrs t'o fthechempers wl' ifigh fiid pied rise and fell with therise: and fe of m on! in. a fir: i .-Q -1h@ r$ #1 49 f Q. ?QQ 9. he ac u t n membee e vl ie ha passageways communigating withlthe firstehaind. with the housing 'The'hbnsiici defines a, piston cylinder havipglapisigon. ee ifrl'yiiigfa joiston rod: attached to fmstfandsecond; valves whiph ayeedapted to open driilcldsihepumb inlet and.

o itlet, the rise an le feli of said dehuat ing member opening a ,ndclosing-the pilotivalve and ea ing IIIQVGi'ifiQI-ifi ofithe pisigon roe} and flow. oivme iif y fgpg the first qhe nlben to me; second chamber and vioeverse qnfactuation of the pum The invention will be described {urlighe11 by ef ien i he aw n Fig. i isja cross sect'ional view. of; one" e v ee 0? my n en i sh n e eli -1;a, nged-,in one position;

a sectional View of a niogli ficaition of the; eppar'a igus" oi l and 2 showingl diapiixagpri enningement in 'the first an'glf eeqm Y 1s-aii d Fig. 4 is. a, sectional View of a fupzthei modifiegtion of the apparatus wherein the, fleet arren emeni re le d' d ee m 9 Clei ns- (01 7193 15) dnit l 6 ise daipted to disei arg ejfliuidjrom vessel H byloiitletllli from ves'sel' l2: oiitiet i8 2 inlei; mjisgpri viqedwim valv fle'anq'in 1 .1.5; is provided. with a, 'siriiile i. valve; 29. "'Ouiile provide; Withfai Valve? i whilgouijleia. I issifni1ar- 1y pltovidedwith a'valveiZZ. Aho isingjii; is genneet'efd tov'essels I l andv l2, respectively; by cfon- I duits24 and ZS'. Thell'ious'iing ZBIoifines a. series of, interconnected, passageways. and valves willf 'befdesoribed, ihjnor'e defail. {Arranged 0,11 basemembe 'zfiwhichsuitably inay be easy; movement. of the sltr'uotu ieis e c piimp 2;! which is connected. to cionfdmt;

musing. as by an inlet 1m izjm gip housing '23 angliconduit by ajd gs line 2 a;

' Arrenged in'the chamber-deli 1 31 031 thevessel |2 an "elongate vert eelgmd 3a which m first and secpnjd sends 1, i eli oi shQi l anolI 32 sligg blyj axranged, on 'thejelfongap rod Q mb 0 isfapfloaifflihr. s ce ale ing 3 4; h gl'1'. allows iil ie fiQ t to 'rise'eind'fail lnfa, m n r w c wi l' be dee r fied urt eii- Th float shall beef Sliglij den fiyiheitq ifivyi li fleet thejrneroury e; will sink thgdrimng; time c n etm intoi ev, ie v 9 9 g lv 3 1 1 .1 base Sl de: membe 3,5 W 1? elifieie t0 17 1591 0 33.331 Q i il hin i i i s into the valve thro g a iu ine ei 7,- The Vli 35 i s eonneetedlto-ihe housing 2 32195? nd ts 38 and VQJVQ 35, 5. 9" connec ed Q 1 P415- 7 3115 1 i u 1 9n fi pl fi nduit 4 3 3926125 h a 5 W th 1711? fifi zsjqipump 7 v t Wi le e n a t e m si 3 e ne e ton cylinder 4 2 in. is arrangedel 'pitonf3. Conneting'to'pisio 531 s e piston rogl 44W V err e'fifr i 1 4 19 1d vel j f l f .5. m i he a ve memb s and i n ie e fi to open and close one d ehergflfi' end sucpion" 28 (i P 11 i manner W i h w he e p' be farmer. ,It wil bseh thatthe housip'gzs" defines chambered? and 48 in' whicl'iiije valves '45 n 14s in abl ar i e 'o 'A ra ngediin ihe 6655 1 H'is a plate 43 which serves t6 prevent eontemineltidn'metvvezi "the drilling fluici and'ifl l eli cli fid bistorijor Body'of mer- Qu y th mi .7 o A ran d n he. e elr U s Q 9 .qr l n fluid 5.0; ab m j ia'e' s While el -j s a hseid of m rcury 5a In' 55 1 12' the. r lli fliiid" is indicated; bynt e r a 1 52 above the float 33 which rests on the'body offlrnercu fyv 53; he e n; It will be noted; thetqthegeondiiitgs 2 s and 25:; are. inticohxiectd anti co neat to We [by the gonduitiz l'. The condu t Z iq 'gon neefgs to the housing 23 and allows communication with the inlet 28. The conduit 24 connects to the housing 23 and provides communication with the outlet 29. The conduit 25 is connected to the housing at two points, a first oint adjacent the inlet 23 and a second point adjacent the outlet 29. the conduit 25 may communicate, on actuation of valve 36, with the inlet 28 and communication may be had between the outlet is and conduit :25. This flow may be readily understood. by reference to Figs. 1 and 2.

Referring now to Fig. 3 which is a further embodiment of my invention, a plurality or pair of vessels 60 and 6! are provided, respectively, with inlets 62 and E3 and outlets 6d and B5. Inlets 82 and 53 are provided with check valves 68 and 57 to resist flow therethrough in a direc tion opposite from that of normal flow while outlets 64 and 65 are similarly provided with check valves 68 and 69 to resist flow back into the vessels {is and 6!. Arranged concentrically in vessels 6% and 5! are cylindrical sleeves iii and H which define a plurality of ports l2 and l3 to allow flow therethrough. Cylindrical sleeves 1G and TH serve as seats for diaphragms i i and '55 which are also concentrically arranged in vessels 6i! and 65 and define therewith outer chambers 16 and W and inner chambers i8 and 58. Inner chamber E9 of vessel 6! is provided with an elongated vertical member 30. Arranged slidably on elongated member 3% is a float 33 provided with a central opening 34. Float 33 in Fig. 3 is similar to but of diiierent dimensions than float 33 to conform to the diameter of sleeve"?! by virtue of being arranged in the inner chamber of vessel 5!. In the embodiment of Fig. 3, the elon= gated member 3i! is about the length of member 30 of Figs. 1 and 2 but is otherwise identical thereto. In this embodiment of my invention, each of the chambers i8 and I9 contains an amount of a non-compressible fluid equal to the volume of the perforated cylinders of sleeves m and H and the interface thereof with the mercury is at least below the bottom shoulder 32 of the member 39 when the respective vessel is beginning to be filled with mercury at the start of a cycle when drilling fluid is being discharged from either the chamber 16 or Ti. The remaining parts of the embodiment of Fig. 3 are identical to the embodiments of Figs. 1 and 2 and further detailed description is not believed necessary.

Referring now to Fig. 4 which is a still further embodiment of my invention, a plurality of vessels Hill and It! are provided, respectivelv, with inlets W2 and E03 and outlets H34 and m5. Inlets E82 and 33 are provided with check valves E05 and it! to resist flow therethrough in a direction opposite from that of normal flow while outlets IM and me are similarly provided with check valves E63 and its to resist flow back into the vessels Hill and EM. Arranged in vessel H1! is a diaphra m member Hill which is arranged concentrically therein which has a cylindrical sleeve H! as a seat ng member defining a plurality of ports I I2 to allow flow therethrough.

Vessel set has a reduced portion H3 in which is arran ed a diaphragm member i M carrying a plate H5. Diaphra m member H4! is attached annularly at ring [16 to the reduced portion 2 !3 of vessel Hill. A cup-shaped member l I! is bolted to the vessel Hit by bolt I !8 to aflix the diaphragm to the vessel I00. The plate [i5 is attached to a rod member H9 which is arranged in a housing 120 which is fluidly connected to conduit 25 and to valve 35. Rod member H9 is provided with a shoulder l2! at its lower end and the rod member H3 is arranged in a yoke [22. The rod member He is slidably seated in the yoke 122 so that it may move vertically therein. The yoke i22 is connected by a second rod member 23 to the slide member 36: of pilot valve 35, the rod member i223 protruding into valve through a stuffing box 33'. The vessel [6i has been illustrated as being similar to vessel (is of Fig. 3. It is to be understood that it may be constructed similar to vessel it with elimination of rod member 5 l9, yoke I22, and rod member I23 which will elimihate the necessity of employing a non-compressible fluid in the chamber 531. As shown, however, vessel It! is provided with a diaphragm H0 which divides the vessel it! into chambers H39 and 53! with the diaphragm H53 in a distended condition by virtue of the chamber it! being filled with mercury and non-compressible fluid. The remaining parts of the embodiment of 'Fig. 4 are identical to the embodiments of Figs.

1 to 3 and further detailed description will not be given.

The apparatus of the present invention functions in the following manner with respect to Figs. 1 and 2. Assuming for the purpose of this description that conduit I3 is connected to a mud or slush pit, the valve i9 is in the open position and drilling fluid or mud indicated as 5!), referring particularly to Fig. l, is being drawn into vessel II. It will be seen that mercury indicated as 5i is contained in vessel 1 l to slightly above the mid-point thereof and is separated from the drilling fluid by a plate 48. The centrifugal pump 2'! is in operation and is withdrawing mercury from vessel l l through conduit 24 which communicates with suction 28 by conduit 24 1-. Thus the mercury is forced to travel through conduit 24 and conduit 24a and thence to suction 28 of pump 2'! since valves and at are in a position to close the conduit 24 from communicating with the discharge 29. The mercury then discharges from the pump 2'! into discharge 29 which communicates with conduit or passageway 25. Thus the mercury flows from conduit 24 into suction 23 and thence through discharge 29 into conduit 25 and thence into vessel 62 where the mercury level is indicated generally by numeral 53. The float 33 rises with the rise of the mercury until the float hits the shoulder 3! in the upper portion of vessel 12. Meanwhile the valve 22 in outlet is open and the mud or drilling fluid 52 is forced out of vessel l2 into conduit it which communicates with the circulating system in the drilling operation as is well-known to the art. The pilot valve 35 is connected by line M3 to the discharge 29 which allows flow of mercury into the piston cylinder and a ainst the piston 43, holding the valves and 46 into the position shown to allow the m rcury to fill completely the vessel 52 and to displace substantially all the mud therefrom.

Referring now to Fig. 2, it will be seen that the drilling fluid 52 has been substantially displaced from the vessel l2 and that the plate 33 has raised the shoulder 33 to its highest position. Referring to vessel ii it will be seen that the vessel is substantially full of drilling fluid and mercury as represented by the portion be neath the plate 3% has been substantially exhausted. The cycle is then reversed and drilling fluid is drawn into vessel 52 from the conduit [3 and inlet 55, valve 20 being in the open position and valve 22 of outlet is being in the closed position. Since the elongated member or rod 30 has-been rai'sedrtheva-lve '35 containingthe slide member 36isnow pushed' upto a position so that the conduits 38 and llrare communicating witheach other and the conduit- 39 allows the mercuryin chamber 42 ahead; ofpi'ston-Ml to be discharged through valve 35 into conduit 4| andthence-into the suction 28 ofpump 21, the mercury-from vessel i'zfbeing discharged by conduit' 25 inter the suction 28 and thenceinto= centrifugal pump Z land outward thercf 1 cm through discharge 29 and conduit 24- into chamber l l With the positions of valves 45=-and 46 as shown in 2 the passageway Z la'isblocked and the mercury moves, following the flowindicated gen.- erally the arrows, allowing it tube pumped from vessel l2 into vessel H causing the mud 5!! therein to flow through outlet Fl by opening valve 2| into conduit I6, inlet line ['4' con:- tainihg valve- I9' being'blocked thereby.

'The embodiment of Fig. works in: amanner similar to that of Figs. 1 and 2 with the d-Ificrence that themercury' is excluded item; contact with the drilling-1 fluid. Inthis embodiment of my invention, Fig. 3 represents the valvefio ina position similar to the arrangement of Fig; 1. In this embodiment, however, the outer. chamber l1 of vessei 6 I is: completely full of drilling flu-id while the inner chamber T8 of vessel 6-D contains substantially its maximum amount of mercury and has arranged above it a non-compressible liquid such as water, and like. The outer chamber 1:8 contains its minimum amount of drilling fluid. Mercury is, therefore, being pumped from inner chamber 18 by condiuts 2:4 and 241 into suction 23- and thence into pumpg'i and. outward therefrom by discharge. 2.9. which communicates with conduit 15. allowing mercury to be delivered; into inner chamber it which also contains a non-compressible liquid such as water, and the like. Since the. float 33 is. at 'itsilowest point and has shoved elongated member 36) dwn- Ward by bearing against shoul-derfi the. discharge 29 communicates by conduits to and :329 with chamber 42 ahead of piston .memberJlB causing thepiston member to. move to the right as far as possible and causing mercury to be discharged from the back of" piston 43 to conduit 3.8. into valve as and thence to the conduit 4| into suction 23 of pump Zia As inner chamber 79 of vessel El. becomes filled to its greatest extent with mercury, the diaphragm "it is dis tended by it memoir-compressible and the drilling fluidin outer chamber 'i'l' will be discharged through discharge 55 by opening valve 69. The outer chamber 6. of the vessel Bil will become filledwith mud while the'mercuryin innervessel Hi thereof will be at its lowest point; thereafter the cycle will-reverse ashas been described with respect to Figs. I and .2.

' The apparatus of Fig. eworks in a manner similar to that of. Figs. 1 to. 3 with the. difference that a non-compressible fluid is not required in the vessel too. In. this embodiment of .my.in vention, however, .a diaphragm H 4 carriesaplate which is connected through members. H9 and ['23 to slide member (it contained in pilot valve 35.. In vessel It! the diaphragm no. is distended by mercury and a. non-compressible fluid arranged above the body of mercury. The

"valve-till is shown in the open-position and drilling mud is being drawn into the outer chamber [30 defined by the diaphragm I Hi and the vessel [01 while the inner chamber I31 defined by the diaphragm is being exhausted of mercury in a direction of flow shown by thearrows. Mercury is. being: dravm. viaconduits and lac: into tion 28: or pum 251: and thence; into outletpafi. and conduit laaand thence by housing; l2ilz-to the undersideo-idiaphragm 11:4; The. slide mem.= ber' 3 61 causes: mercury to pump by;- discharge 29 into conduitz'tiu and: thence by. conduit 3.9; into chamber 42: andlag-ainst: the piston es arranged in cylinder causing: the piston. to move to. the right: and: causing the valve; members; 55- and #35 carried? by piston rod: 64?. to; also move. the; right to the farthest extent. .Mercury is. discharged from cylinder 4'22 by conduit 313 and thence into valve '35iand back into; the pump. suction. 28. by conduit M. As the-mercury-rises: underthcrdiaphragm H4. it is moved, upwardly forcing drill= mg mud contained: in vessel no outwardl by outlet I04; check value [0.8; being opened. As the mercury substantially fillsychamber tilil under diaphragm I'M: the cycle is reversed when. the shoulder I22 I reaches thelimitof its upward: travel and causes a vertical: movement (Ii-yoke I22. and connecting rod I 2.3: and; corresponding: upward movement oi slidemem ber 3150i: valve 351 which 7 allows: the pilot valve to, assume the. position shown in Fig. 2 which causesxthe. slide. members 4 5 and 46 carried bypiston rod, is to move to the left causing mercury toflow into inner charm ber I31 of vessel or. Thereafter the cycle will reverse as. has. been previously described. It will be understood, of course, that, whenvessel. lill is constructed like vessel. N10,. it'wil-l be unnecessary to use a non-compressible fluid therein.

It will. be. seen from the .foregoing: description taken with the. drawing that ;subs.tantia 1 advantages inure to. the present invention. All of the moving parts except .thesmotivating means (not shown -for pumpqzl are enclosed eliminating the-possibility of leaks. around, or in packing glands and. permitting the use. of. a. h

replace these various. elements at frequent intervals due toscorin-g and erosion.

While water is mentionedas. the. nonscom pressible liquid employed in-the innerchambers "of'Figs. 3 and 4,'o.thcr non-compressible liquids may besubstituted therefor such as selected low viscosity, .nonevolati le hydrocarbon fractions. For example a hercseneor gas oil fraction. may suitably be used. When hydrocarbon fractions are employed as the. non-compressible liquid the constructional material forthe. diaphragm shou be. selected'to. resist attack by the hydrocarbon.

Various syntheticrubberstare available on the market which resist; attack by hydrocarbons.

The nature and objects of the. present invention having been completely describedand illustrated, what 'I wish to claim as new and useful and to secure by Letters Patent is:

1. A paratus for pumping drillingfiuid which comprises, incombinatioma pair of intercon-= :nected vessels defining first and second chambars a liquid pistonarranged in and adapted with a valve adapted to resist flow o1 fluid'in. a direction opposite to normal flow through said inlets and outlets, a housing provided with a piston cylinder, interconnected first and second conduits connected to said housing and to said second chamber fluidly communicating said housing with said second chamber, interconnected third and fourth conduits connected to said housing and to said first chamber fluidly communicating said housing with said first chamher, a centrifugal pump, conduits defining an inlet to and an outlet from said pump fluidity connected to said housing and to said pump,

elongated member vertically arranged in the first of said chambers with respect to the horizontal axis of said apparatus extending substantially the length thereof defining first and second shoulders at points corresponding generally with first and second ends of said first chamber, a float having a central opening slidably mounted on said elongated member adapted to raise and depress same on rise and fall of said float, a pilot valve adapted to be actuated by said float connected to said first chamber and to said elongated member and communicating fluidly with said first chamber and with said third con duit and with the piston cylinder defined by said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and to said first conduit, a piston arranged in cylinder, and a piston rod attached to said piston and to said first and second'valves, the rise and fall of said float actuating said pilot valve tocause movement of said liquid piston into said piston cylinder and against said piston attached to said piston rod and from said. first r to said second chamber and vice versa on 2162. 1 ation of said pump.

2. Apparatus in accordance with claim 1 in which the liquid piston comprises a body of mercury.

3. Apparatus for pumping drilling fluid which comprises, in combination, a pair of first and second interconnected vessels, a diaphragm in each of said vessels defining an inner chamber and an outer chamber, said outer chambers being adapted to receive drilling fluid, an inlet and an outlet in each of said outer chambers provided with means adapted to resist flow of drilling fluid in a direction opposite to normal flow through said inlets and outlets, a liquid piston arranged in and adapted to reciprocate between said inner chambers, a housing provided with a piston cylinder, interconnected first and second conduits connected to said housing and to said vessel fluidly communicating said housing with a second of the inner chambers, intercom nected third and fourth conduits connected to said housing and to said first vessel fluidly communicating said housing with a first of the inner chambers, a centrifugal pump, conduits defining an inlet to and an outlet from said pump connected to said housing and to said pump, an elongated member arranged vertically in the first of said inner chambers with respect to the horizontal axis of said apparatus extending substantially throughout the length thereof defining first and second shoulders at points corresponding generally to first and second ends of said first inner chamber, a float having a central opening slidably mounted on said elongated member adapted to raise and depress same on the rise and fall of said float, a pilot valve adapted to be actuated by said float connected to said first vessel and to said elongated member fluidly communicating with said first inner chamber and said housing and with the piston cylinder defined by said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and to said first conduit, a piston arranged in said piston cylinder, and a piston rod attached to said piston and to said first and second valves, the rise and fall of said float actuating said pilot valve to cause movement of said liquid piston into said piston cylinder and against said piston attached to said piston rod and from said first inner chamber to said second inner chamber and vice versa on actuation of said pump.

4. Apparatus in accordance with claim 3 which the liquid piston comprises a body of mercury.

5. Apparatus for pumping drilling fluid which comprises, in combination, a pair of interconnecting vessels, a diaphragm in a second of said vessels defining an inner chamber and an outer chamber, said outer chamber being adapted to receive a body of drilling fluid, an inlet and outlet for said outer chamber provided with means to resist flow of drilling fluid in a direction opposite to normal flow through said inlet and outlet, a diaphragm in a first of said vessels defining an upper and a lower chamber, said upper chamber being adapted to receive a body of drilling fluid, an inlet and an outlet for said upper chamber provided with means to resist flow of drilling fluid in a direction opposite to normal flow through the inlet and outlet in said upper chamber, a liquid piston arranged in and adapted to reciprocate between said inner chamber and said lower chamber, a housing provided with a piston cylinder, interconnected first and second conduits connected to said housing and to said second vessel fluidly communicating said housing with said inner chamber, interconnected third and fourth conduits connected to said housing and said first vessel fluidly communieating said housing with said lower chamber, a centrifugal pump, conduits defining an inlet and an outlet to said pump connected to said housing and to said pump, an actuating member connected to the diaphragm in said first vessel, a pilot valve connected to said first vessel and to said actuating member fluidly communicating with said lower chamber and with said housing and with the piston cylinder defined by said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and to said first conduit, a piston arranged in said piston cylinder, and a piston rod attached to said piston and to said first and second valves, the rise and fall of said diaphragm in said first vessel actuating said pilot valve to cause movement of said liquid piston into said piston cylinder and against said piston and from the lower chamber to the inner chamber and vice versa on actuation of said pump.

6. Apparatus in accordance with claim 5 in which the liquid piston comprises a body of mercury.

7. Apparatus for pumping drilling fluid which comprises, in combination, a plurality of interconnected vessels defining at least first and second chambers, a liquid piston arranged in and adapted to reciprocate between said chambers, an inlet and an outlet for each of said chambers provided with means adapted to resist flow of fluid in a direction opposite to normal flow through said inlets and outlets, a housing providedwith a piston cylinder, interconnected first and second conduits connected to said housing and to said second chamber fluidly communieating said housing with said second chamber, interconnected third and fourth conduits connected to said housing and to said first chamber fluidly communicating said housing with said first chamber, a pump, conduits defining an inlet to and an outlet from said pump connected to said housing and to said pump, an actuating member extending into said first chamber adapted to be actuated by a reciprocation of said liquid piston in said first chamber, a pilot valve connected to said actuating member communicating fluidly with said first chamber and with said third conduit and with the piston cylinder defined by said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and to said first conduit, apiston arranged in said cylinder, and a piston rod at= tached to said piston and to said first and second valves, the actuation of said actuating member shifting said pilot valve to cause movement of said liquid piston into said piston cylinder against said piston attached to said piston rod and from said first chamber to said second chamber and vice versa on actuation of said pump.

8. Apparatus for pumping drilling fluid which comprises, in combination, a plurality of interconnected vessels defining at least first and second chambers containing a body of mercury, an inlet and outlet for each of said chambers provided with means adapted to resist flow of fluid in a direction opposite the normal flow through said inlets and outlets, a housing provided with a piston cylinder, interconnected first and second conduits connected to said housing and tosaid second chamber fluidly communicating said housing With said second chamber, interconnected third and fourth conduits connected to said housing fluidly communicating said housing with said first chamber, a pump, conduits defining an inlet to and an outlet from said pump connected to said housing and to said pump, an actuating member arranged in said first chamber adapted to rise and fall with the rise and fall of mercury in said first chamber, a pilot valve connected to said actuating member fluidly communicating with said first chamber and with said third conduit and with the piston cylinder defined by said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and to said first conduit, a piston arranged in said cylinder, and a piston rod attached to said piston and to said first and second valves, the rise and fall of said actuatin member shifting said pilot valve and causing flow of mercury against said piston and movement thereof and flow of mercury from said first chamber to said second chamber and vice versa on actuation of said pump.

9. Apparatus for pumping drilling fluid which comprises, in combination, at least first and second interconnected vessels, a diaphragm in each of said vessels defining first and second inner chambers containing a body of mercury and a body of a non-compressible liquid and first and second outer chambers adapted to receive drilling fluid, an inlet and an outlet for each of said outer chambers provided with valve members adapted to resist flow of drilling fluid in a direction opposite the normal flow through said 1 inlets and outlets, a housing provided with a piston cylinder, interconnected first and second conduits connected to said second vessel and to said housing fluidly communicating said housing with said second vessel, interconnected third and fourth conduits connected to said housing and to said first vessel fluidly communicating said housing with said first vessel, a pump, conduits defining an inlet to and an outlet from said pump connected to said housing and to said pump, an elongated member arranged in a first of said inner chambers extending substantially the length thereof defining first and second shoulders at points corresponding generally to first and second ends of said first inner chamber, a float having a central opening slidably mounted on said elongated member adapted to raise and depress same on rise and fall of said float, a pilot valve connected to said elongated member fluidly communicating with said first vessel and with the piston cylinder in said housing, first and second valves in said housing adapted to connect sequentially said pump inlet to said second conduit and to said third conduit and said pump outlet to said fourth conduit and said first conduit, a piston arranged in said piston cylinder, and a piston rod attached to said piston and to said first and second valves, the rise and fall of said float actuating said pilot valve to cause flow of mercury against said piston and movement thereof and flow of mercury from said first inner chamber to said second inner chamber and vice versa on actuation of said pump.

DOUGLAS RAGLAND.

Number Name 343,568 Cooper June 15, 1886 2,538,842 McFarland Jan. 23, 1951 

